Pure wild boar were not introduced into the New World until the 19th century. The suids were released into the wild by wealthy landowners as big game animals. The initial introductions took place in fenced enclosures, though several escapes occurred, with the escapees sometimes intermixing with already established feral pig populations. The first of these introductions occurred in New Hampshire in 1890. Thirteen wild boar from Germany were purchased by Austin Corbin from Carl Hagenbeck, and released into a 9,500 hectare game preserve in Sullivan County. Several of these boars escaped, though they were quickly hunted down by locals. Two further introductions were made since the original stocking, with several escapes taking place due to breaches in the game preserve's fencing. These escapees have ranged widely, with some specimens having been observed crossing into Vermont. In 1902, 15-20 wild boar from Germany were released into a 3,200 hectare estate in Hamilton County, New York. Several specimens escaped six years later, dispersing into the William C. Whitney Wilderness Area, with their descendants surviving for at least 20 years. The most successful boar introduction in the US took place in western North Carolina in 1912, when 13 boars of undetermined European origin were released into two fenced enclosures in a game preserve in Hooper Bald, Graham County. Most of the specimens remained in the preserve for the next decade, until a large-scale hunt caused the remaining animals to break through their confines and escape. Some of the boars migrated to Tennessee, where they intermixed with both free ranging and feral pigs in the area. In 1924, a dozen Hooper Bald wild pigs were shipped to California and released in a property between Carmel Valley and the Los Padres National Forest. These hybrid boar were later used as breeding stock on various private and public lands throughout the state, as well as in other states like Florida, Georgia, South Carolina, West Virginia and Mississippi.

Several wild boars from Leon Springs and the San Antonio, Saint Louis and San Diego Zoos were released in the Powder Horn Ranch in Calhoun County, Texas, in 1939. These specimens escaped and established themselves in surrounding ranchlands and coastal areas, with some crossing the Espiritu Santo Bay and colonising Matagorda Island. Descendants of the Powder Horn Ranch boars were later released onto San José Island and the coast of Chalmette, Louisiana. Wild boar of unknown origin were stocked in a ranch in the Edwards Plateau in the 1940s, only to escape during a storm and hybridise with local feral pig populations, later spreading into neighbouring counties. Starting in the mid-80s, several boars purchased from the San Diego Zoo and Tierpark Berlin were released into the United States. A decade later, more specimens from farms in Canada and Białowieża Forest were let loose. In recent years, wild pig populations have been reported in 44 states within the US, most of which are likely wild boar-feral hog hybrids. Pure wild boar populations may still be present, but are extremely localised.